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Offline nobby

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newbie help please
« on: February 21, 2014, 10:40:20 AM »
hello, still in demo mode.
the machine is an isel fb2 16mm with 5mm pitched threads
neama 3.1's bi-polar parrallel
drives are set 3.2 a and 2 micro steps
leafboy usb bob



only two issues!!!

draw a box 100mm by 50mm in corel, export it as a dxf to corel cad.
import that into lazy cam - make the g-code.
send it to mach3,
the problem is the machine moves a mere exact half, 50 by 25mm instead of 100 by 50mm
do i change the 'steps per' from 400 to 800?
velocity stays at 750?
acceleration 24
is it better to have 'more' micro steps set on the drives than 2?
i.e. if I have 2 steps at 800 steps per  - if thats correect?
can I have 20 steps at 8000
or is that not how it works?

ALSO, my Z axis is set up just as the X and Y axis are - they trun the corrcet way, but the Z turns the wrong way goes up instead of plunges, and goes down at the end of the box

is that a wireing issue? as I changed the a- and aaaaaaaa+ around and the b+ and b- around and it dint make any difference.
thank you please

p.s. who do I send the pay-pal to?
« Last Edit: February 21, 2014, 10:49:39 AM by nobby »

Offline Hood

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Re: newbie help please
« Reply #1 on: February 21, 2014, 10:47:37 AM »
The Z is simple, just go to Config menu then Ports and Pins then Motor Setup and change the active state of the Z Dir pin.

For the distance it could be simply you have not calculated your steps per unit correctly, if you double the steps per unit for X and Y it should make your distance closer, however you should really make sure you have calculated them correctly.
Hood

Offline nobby

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Re: newbie help please
« Reply #2 on: February 21, 2014, 10:56:18 AM »
change the direction pin on the z axis to what though??
it says 8 at the moment?
enabled = tick
step pin 4
direction pin 8
dir low = tick
step low = tick
step port = 1
dir port = 1


oh, so I do simply double the steps per?

is it 'better to have more micro steps on the drives and a higher number in the steps per?

Offline nobby

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Re: newbie help please
« Reply #3 on: February 21, 2014, 11:30:52 AM »
great so now set to 64 steps at 25600 steps per
seems lovely

oh i see, its all about setting the machine for the speed you need rather than total speed = derrr i have set it too fast then
typical newbie to cnc, and having a sign cutting plotter on full chat = trying to speed it up all the time.
great
« Last Edit: February 21, 2014, 11:45:31 AM by nobby »

Offline ZASto

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Re: newbie help please
« Reply #4 on: February 21, 2014, 11:34:38 AM »
For Z axis
dir low = UNtick <-
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Offline nobby

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Re: newbie help please
« Reply #5 on: February 21, 2014, 11:45:51 AM »
thats the trick
fgantastic

Offline nobby

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Re: newbie help please
« Reply #6 on: February 21, 2014, 12:42:13 PM »
right oh, next on the adjenda are the limit switches, whats all that about
can I assign a 2 foot square work area to mach3?

also, i have earth/ground wires fitted at the motors, do I attatch them to the earth on the power supply.





« Last Edit: February 21, 2014, 12:46:26 PM by nobby »

Offline Fastest1

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Re: newbie help please
« Reply #7 on: February 21, 2014, 02:49:19 PM »
I responded on your other thread about limits and a host of your other questions.

You will also have to be more clear on your questions as these topics leave the potential for damage and injury to machines and humans.

"also, i have earth/ground wires fitted at the motors, do I attach them to the earth on the power supply?"

First lets make sure we are talking the same terms.

Are you referring to the spindle motor?

or a stepper motor?

A stepper motor does not require a direct connection to your power supply, it is hooked to a driver (which is hooked to the DC power supply, not always but generally as far as hobby machines go)

The spindle motor on the other hand would need to be grounded.

There is also the case of shielding. Are you referring to the bare braided wire of the stepper wires bundle (or possibly any wire)? These are to stop stray voltages/EMI/Static etc from triggering an input or output.

In most hobby machine practices these are connected to the "star ground" on the controller cabinet end only. This is a complicated topic and has a few variables. Commercial machines connect it at both ends. Also chassis and earth grounds are tied in too.

Take pictures and post them to during your questions if possible. It helps all who read them and we like pictures.
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Offline nobby

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Re: newbie help please
« Reply #8 on: February 21, 2014, 04:44:08 PM »
oh - I hear you!!!
no, its simply a ground wire riveted to the little square cans that cover the motors!! - phew.
all the cabling is original and sheilded, the earth/ground wire comes down with them inside the sheilding.
just wonderedif I connect these three grounds to the enclosure/box, then take one from the power supplies earth ground to that, the eclosure is metal
and the psu is bolted to that - so just to the case then?

what do you mean by 'star'

Offline Fastest1

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newbie help please
« Reply #9 on: February 21, 2014, 05:14:18 PM »
Star is a central point in which all grounds are brought. In my understanding this leaves only 1 path to ground. Having multiple places where grounds attach even to a conductive frame is a no no.

If you are not a member of CncZone I suggest you join there too. Look at the "general electronics" section. There is plenty of information (and debate) on the topic. It is worth a look.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)